A significant and growing chasm has opened between the U.S. and Europe, endangering our most fundamental global alliance. Europe’s growing mistrust and anger with America threatens our NATO-grounded national security partnership and our economic trade with the European Union.

The recent imposition of U.S. tariffs on steel and aluminum imports could be the final straw. The EU has now opened a case with the World Trade Organization, claiming the U.S. imposition is illegal. EU Commission President Jean-Claude Juncker has called the process “stupid.”

Most of my 16 years living overseas have been in Europe—France, Germany, Belgium. I can confidently say that U.S.-Europe relations are at their lowest point in modern history. The situation is dire and worsening. It deserves thoughtful examination on both sides of the Atlantic.

It’s first worth exploring why our relationship with Europe is important in the first place. After all, the U.S. remains the most powerful, well-armed, and influential society in the world. We have top-notch science, agriculture, manufacturing, higher education, and health care.

Yet at the same time, we benefit greatly from a strong partnership with our neighbors across the Atlantic. Europeans largely share our values. We have a common and integrated trade relationship worth nearly $1.1 trillion. The U.S. is overwhelmingly the EU’s largest trading partner if considered as a single entity, exceeding China, Canada, and Mexico. NATO is without question America’s most important defense alliance. Europe helps the U.S. lead globally, mostly supporting us in the United Nations and other international alliances. And reinforcing all this, our government and politics are fundamentally based on British and French political history.

It’s clear that if America hopes to continue its global leadership, we need Europe. To fix our alliance, we need to start by recognizing that the chasm between us and Europe is not simply based in policy. It’s true that we currently have major disagreements around the Paris climate accord, the Iran nuclear deal, and the relatively low amount European countries invest in their own defense. But other major factors also separate us.

The fundamental challenge is that Europeans loathe U.S. President Donald Trump. This is understandable. He has publicly disparaged NATO and personally rebuked European leaders like German Chancellor Angela Merkel and British Prime Minister Theresa May. His shifting policy positions, continual misstatement of facts, and “America First” sloganeering have unnerved our European allies. In addition, there is no longer a common, galvanizing Russian enemy to unite Americans and Europeans.

So, what is to be done? As an infantry company commander in Vietnam, when we were engaged in high-intensity combat, we would fire red star clusters, or flares, up into the night air to signal “danger close.” All U.S. forces knew then that they must immediately come to our aid.

Our relationship with Europe is now “danger close.” Congress, the business community, academia, and the media must shine light on the growing danger of the chasm dividing us from Europe.

Barry McCaffrey is a retired U.S. Army four-star general. He is a national security analyst for NBC and a member of the Council on Foreign Relations. He served on the U.S. Military Academy (West Point) faculty for seven years, teaching national security studies and political science. He was wounded in action three times during his four combat tours.